INSW20 Posted January 23, 2021 Report Share Posted January 23, 2021 Is that what I'm getting here? Quote Link to comment Share on other sites More sharing options...
Adamw Posted January 23, 2021 Report Share Posted January 23, 2021 I doubt that 0.85 lambda at idle would be rich enough to make it misfire. But the quick test to confirm would be to make it 15% leaner and see if it is any different. Lambda probes cant always give you the full picture of what is going on in combustion. Quote Link to comment Share on other sites More sharing options...
ellisd1984 Posted January 23, 2021 Report Share Posted January 23, 2021 I've got a St205 and when roughing in my fuel map the car would comfortably drive around at 0.7 lambda, obviously didn't want it there but it certainly wouldn't splutter or miss. Quote Link to comment Share on other sites More sharing options...
INSW20 Posted January 24, 2021 Author Report Share Posted January 24, 2021 Thanks! I'll lean it out and see if it's any better, or at least not worse Quote Link to comment Share on other sites More sharing options...
koracing Posted January 24, 2021 Report Share Posted January 24, 2021 Typically a misfire will show as a lean spike or overall leaner running average than reality. I've had cars run on dyno so rich they did misfire, and the AFR looked like it was spot on, lol. I removed 15% fuel and the afr read richer without misfiring. Rich misfire sounds like a limiter being applied usually. I would guess you're more likely having a trigger threshold error. What is the arming voltage (logged) versus actual trigger1/2 values at that rpm? Can you run a trigger test at the rpm where that was happening? INSW20 1 Quote Link to comment Share on other sites More sharing options...
INSW20 Posted January 25, 2021 Author Report Share Posted January 25, 2021 Yep, and that's what was so confusing to me. Any misfire should show lean, so I don't know why it's showing rich when it stumbles for a split second. This should be the trigger scope from idling during warmup at about 1200rpm: Trigger arming threshold is 0.6V at that point. Do I need to bump that to 1.2-1.5V? Quote Link to comment Share on other sites More sharing options...
dx4picco Posted January 25, 2021 Report Share Posted January 25, 2021 Maybe increase a bit the trigger 2 threshold. I will let Adam give the last word but it looks like the small hump on there may give you an error INSW20 1 Quote Link to comment Share on other sites More sharing options...
INSW20 Posted January 26, 2021 Author Report Share Posted January 26, 2021 Leaned it out a little bit and increased trigger threshold and it's still got some dips/stumbles. Maybe it's just the old fuel (E85, 9-10 months old) that needs to finish burning out of the tank... It seems to be better when it's warmer and any time I bring the revs up. Quote Link to comment Share on other sites More sharing options...
Adamw Posted January 26, 2021 Report Share Posted January 26, 2021 It would be best to post the actual log and tune, there is a whole lot of variables that can affect mixture that are not shown in the screenshot above. Whats it got for a lambda controller? Its a bit odd that post start enrich pulls out about 60% extra fuel over 20 seconds but the average measured lambda over that period only changes by ~15%. Quote Link to comment Share on other sites More sharing options...
INSW20 Posted January 26, 2021 Author Report Share Posted January 26, 2021 Here is my most recent map and useful log file for this. It's using an AEM 30-4110 that was calibrated in open air and then again in a fuel vapor environment to get full-rich and full-lean readings to plug into the cal table. I've confirmed I'm not getting trigger errors now, also. Quote Link to comment Share on other sites More sharing options...
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